MXPA99011272A - A dose setting mechanism and an injection syringe having such a dose setting mechanism - Google Patents

Abstract

A dose setting mechanism for a drug administration device and an injection syringe having such a dose setting mechanism are provided. The injection syringe has a housing accommodating an ampoule (3) containing medicine sufficient for a number of dosed injections, an injection press button (7), a piston rod (13) for co-operation with a piston in the ampoule (3) when injecting, and a dose setting mechanism comprising a rotatable dose setting element (5) interconnected with the press button. The dose setting mechanism further comprises a dose administration wheel (11) connected with the piston rod (13) and a coupling ring (12) connected with the dose setting element (5) and the press button (7). One of the dose administration wheel (11) and the coupling ring (12) at least partly surrounds the other, andthe dose administration wheel (11) and the coupling ring (12) are arranged such that rotation of the dose setting element (5) allows the coupling ring (12) to be rotated in either direction in relation to the dose administration wheel (11), while activation of the press button (7), and thereby rotation of the coupling ring (12), causes the dose administration wheel (11) to be rotated.

Description

DOSE ADJUSTMENT MECHANISM AND AN INJECTION SYRINGE THAT INCLUDES DESCRIPTION OF THE INVENTION The invention relates to a dose adjustment mechanism for a medicament delivery device having a housing and a push button that can be connected to the piston rod for administration of a dose set from a container, the dose adjustment mechanism it comprises a rotary dose adjustment element interconnected with the button for pressing. Drug delivery devices that have a dose adjustment mechanism are known in many different types, for example, syringes, inhalers, sprays, etc. The purpose of these drug delivery devices is to make the user capable of establishing an individual dose of drug to be administered.Injection syringes are better known in the art for use in patients, mainly diabetics, who must inject themselves with individually set doses of medicines, for example, insulin. Such syringes are often provided with forms such as a REF .: 32131 pen so that they can be transported by the patient throughout the day and be ready for use at all times, when the dose is to be established in these syringes. injection in the form of a pen, a cap covers the portion of the needle of the syringe and is rotated, which causes a button to press on the opposite end of the injection syringe moves outward. The button to press frequently has a scale on the axis that connects the button to press with the inside of the injection syringe, and you can read the dose set on this scale. After setting the dose, the user moves the lid of the needle portion, inserts the needle into an area to be injected and injects the medicine by pressing the button to press. When the button to press reaches the bottom, the established dose has been injected. A disadvantage of these pen injection syringes is that the scale on the pressing button tree has small divisions and digits due to the limitations established by the perimeter of the tree. If the user is visually impaired, as is the frequent case with diabetics, this can cause a wrong adjustment of the dose which has serious consequences for the user. An attempt to overcome this disadvantage is described in DE 4 208 677 which shows an injection syringe which provides with a dose adjustment scale having large digits. The dose adjustment device consists of a box-like container into which an injection syringe can be placed. When the dose is established, a stop is moved over the piston rod of the injection syringe until the correct dose, read on the scale, has been established. When the user removes the injection syringe from the dose adjustment device and injects himself as usual with a common injection syringe, the stop on the piston rod determines the dose to be injected. All known injection syringes have dose setting devices which have the disadvantage that the dose setting device, or at least part of it, must be removed from the injection syringe after it has been established to the injection syringe. dose, but before the injection is carried out. Some of the injection syringes, as is the case as described in DE Al 4 208 677, even have the "aversion" that the established dose can not be verified after the dose adjustment device has been removed since the syringe Injection itself does not have a means of scale It is an object of the present invention to provide a dose adjustment mechanism that can be constructed in a drug delivery device, for example, an injection syringe, which can not be removed from it and that provides the possibility of establishing a dose and repent and correct the established dose. In addition, there is always a complete correspondence between the movement of the dose adjusting element of the movement of the button to press in order to assure the user of the established dose and the administered dose. This is obtained by a dose adjustment mechanism of the type mentioned in the opening paragraph of this specification, which is characterized in that the dose adjustment mechanism further comprises a dose management wheel connected to the piston rod and a ring of coupling connected to the dose adjustment element and the button to press, one of the dose management wheel and the coupling ring at least partially surrounds the other, the dose management wheel and the coupling ring are placed Thus, the dose adjustment element allows the coupling ring to rotate in any direction relative to the dose management wheel, while the activation of the button to press, and therefore the rotation of the coupling ring, causes turn the dose management wheel. The arrangement of the dose adjustment mechanism in this manner provides a dose adjustment mechanism which can be completely constructed in a drug delivery device, for example, an injection syringe, and has the possibility of adjusting a dose and dosage. repent and correct the established dose. Since the dose setting element is connected to the coupling ring which in turn is connected to the button for pressing, a complete correspondence is obtained between the movement of the dose adjustment element of the movement of the button to press. In order to obtain cooperation between the dose management wheel and the coupling ring, these parts can advantageously be positioned as set forth in claim 2. Claim 3 further discloses arrangements according to a preferred embodiment. By incorporating all these features, a particularly simple construction is obtained that needs only four parts for the construction of a dose adjustment mechanism, i.e., the dose adjustment element, the dose management wheel, the coupling ring and the button to press. The invention also relates to an injection syringe comprising a housing that accommodates an ampoule containing sufficient medicine for several metered injections, a push button that applies the injection, a piston rod for cooperation with a piston in the ampoule when injected, and a dose adjustment mechanism comprising a rotatable dose adjustment element interconnected with the push button. The injection syringe is further characterized in that the dose adjustment mechanism includes the features mentioned in claim 1. By placing the injection syringe in this manner, an injection syringe is obtained which has a dose adjustment mechanism interconstituted with the possibility of adjusting the dose and repent and correct the established dose. Since the dose adjustment element is connected to the coupling ring which in turn is connected to the button for pressing, a complete correspondence between the movement of the dose adjustment element and the movement of the button to press is obtained. The connection between the different parts of the dose adjustment mechanism is preferably as mentioned in claim 5 and 6, which "provides the aforementioned advantages." In a preferred embodiment, the housing has a means to prevent the wheel from rotating. administration of doses in a direction corresponding to the removal of the piston from the ampoule., when using the dose adjustment mechanism in an injection syringe, that the piston rod is never removed from the piston in the vial but always in firm contact with the piston. If the piston rod is removed from the piston, the injected dose would not correspond to the established dose, due to the separation between the piston rod and the piston. Preferably, the dose management wheel is connected to the piston rod by means of a gear wheel that is provided in the center of the dose management wheel. Preferably, the injection syringe is provided with a scale and an indicator indicating the dose established when the dose setting element is rotated. More advantages and mode of operation of the dose adjustment mechanism will be more fully described in the following with reference to the drawings, in which: Figure 1 shows a top perspective view of a modality of the injection syringe having a dose adjustment mechanism, according to the invention, Figure 2 shows an exploded view of an embodiment of an injection syringe having a dose adjustment mechanism, according to the invention, Figure 3 shows the dose adjustment mechanism, when a dose is adjusted, Figure 4 shows the dose adjustment mechanism when a set dose is regressed and corrected, and Figure 5 shows the mechanism of dose adjustment when an established dose is administered .

Figure 1 shows an injection syringe 1 having a dose adjustment mechanism according to the present invention. The syringe has a first housing part 2 containing an ampule 3 with medicine, for example insulin, the ampoule 3 is seen through a window in the first housing part 2, and a second housing part 4 covering the mechanism of dose adjustment. The first part of two housing generally has a pen shape, as is known from commercially available injection syringes. The syringe further comprises a dose adjustment mechanism, of which a rotating disc-shaped dose adjusting element 5 is observed, having a grip 6 for the fingers and a button 7 for pressing, which applies the injection, in addition , a needle 8 is shown extending from the lower end of the injection syringe 1. The size of the embodiment shown of an injection syringe 1 and in particular of the dose adjustment element 5 is such that it is adjusted to the user's hand when adjusting a dose of medicine to retain the injection syringe 1 in one hand as well as when adjusting the dose by rotating the dose adjustment element 5 with the other hand, and also when injecting the set dose when holding the injection syringe 1 in a "hand and when pressing the button 7 to press with the thumb in the same hand A scale 9 is provided in the dose adjustment element 5, and an indicator 10 is provided in the second housing part 4. Figure 2 shows an injection syringe 1 in an exploded view showing again the first and second housing parts 2 and 4, ampule 3, dose adjusting element 5, button 7 for pressing and needle 8. Injection syringe 1 further comprises a dose management wheel 11, a ring 12 coupling, a piston rod 13 and a needle coupling part 14. The dose adjustment mechanism comprises the element for dose adjustment, the dose management wheel 11, the coupling ring 12 and the button 7 for pressing. These parts will be described in greater detail in the following since these parts constitute a preferred embodiment of the invention. The dose adjusting element 5 is disc-shaped and has a grip 6 for the fingers and a pin 15 projecting downwards on the periphery, the tang interacts with a notch 16 which is provided on the edge of the coupling ring 12 . The coupling ring 12 in turn is in engagement with the button 7 for pressing by means of a gear wheel 17 which is provided in the hub of the ring 12 of the coupling and a toothed portion 18 of the button 7 for pressing. the dose adjustment element 5 is connected to the coupling ring 12 which in turn is connected to the button 7 for pressing, a complete correspondence between the movement of the dose adjustment element 5 and the movement of the button 7 is obtained This means that whenever the dose adjusting element 5 is rotated to adjust or regress and correct a dose, the button 7 for pressing moves outside or inside the housing of the injection syringe 1. Similarly, when press the button 7 to press in order to inject a set dose, the dose adjustment element 5 rotates back to its initial position.This means that the user can visually observe that the established dose is injected during the injection act. The coupling ring 12 consists of a ring segment connected to a hub at each end thereof. At one end, the ring segment is rigidly connected to the hub by means of a rigid part 19, and at the other end the ring segment is flexibly connected to the hub by means of a flexible part. The flexible part 20 is included to facilitate assembly of the coupling ring, but can be omitted without changing the work of the dose adjusting mechanism.

The interaction between the coupling ring 12 and the dose management wheel 11 will now be fully explained with reference to Figures 3-5. Figure 3 is a top view of the dose adjustment mechanism when a dose is set, which shows the first and second housing part 2 and 4, the dose management wheel 11, the coupling ring 12, the upper part of the piston rod 13, the button 7 for pressing and the toothed part 18. The dose adjustment element 5 is omitted in order to show the interior of the dose setting mechanism, but when used, its pin 15 projecting downwards is in permanent engagement with the notch 16 which is provided on the edge of the coupling ring 12. The coupling ring 12 is formed in a manner that partially surrounds the dose-administering wheel 11, and it is noted that the dose-administering wheel 11 is provided with projections 21 at its outer periphery, and that part of the ring 12 of coupling is provided with similar projections 22. When a dose is to be set, the dose setting element 5 is rotated in the clockwise direction according to the arrow S. This causes the coupling ring 12 to rotate in a clockwise direction, the projections 22 of the coupling ring 12 sliding over the projections 21 of the dose management wheel 11. The second housing portion 4 is provided with an inwardly projecting pawl 23 which, in cooperation with the projections 21, which are provided on the dose-management wheel 11, prevents the dose-management wheel 11 from rotating in clockwise, which would cause the rod 13 of the piston to be removed from the ampule 6. Turning the coupling ring 12 causes the button 7 to press to move upward according to the arrow U due to the coupling of the gear wheel 17 (figure 2) on the coupling ring 12 ^ and the toothed part 18 of the button 7 for pressing. If the established dose is corrected, the dose adjustment element 5 is rotated in the counterclockwise direction, according to the arrow R in the figure 4. Due to the flexible part 20 of the coupling ring 12 (FIG. 2), the coupling ring 12 expands outwards, as shown, which allows the projections 22 to slide over the projections 21 of the dose-management wheel 11. Therefore, the dose management wheel 11 is not affected by this counterclockwise rotation of the coupling ring 12.

The counterclockwise rotation of the dose setting element 5 causes the button 7 to press to move downwards, according to the arrow D. Some kind of resistance can be provided to "impede the movement of the button 7 to press in order to ensure that the coupling ring 12 expands outwards when a dose is corrected.When a set dose is to be injected, the button 7 is pressed to press, downward according to the arrow P in Figure 5. This causes the coupling ring 12 to rotate in a counterclockwise direction, as indicated by the arrow I due to engagement of the toothed portion 18 of the button 7 to press when the wheel 17 of gear (figure 2) of the coupling ring 12. Due to the fact that the rotational force from the button 7 for pressing is transferred to the ring segment of the coupling ring 12 by m When the rigid portion 19 is not in use, the ring segment does not expand, as would be the case when an established dose is corrected by rotating the dose adjustment element 5 in a counterclockwise direction, but tightened around of the dose management wheel 11, which causes the projections 22 of the coupling ring 12 to engage with the projections 21 of the dose management wheel 11.

Some type of resistance can be provided by preventing movement of the coupling ring 12 at the flexible connected end of its ring segment in order to ensure that it is tightened around the delivery wheel 11 when an established dose is injected. The coupling between projections 22 of the coupling ring 12 and the projections 21 of the dose-management wheel 11 cause the dose-management wheel 11 to rotate counterclockwise, which in turn causes the piston rod 13 moves forward in the ampoule 3 due to the interaction of a gear wheel 24 that is provided in the hub of the dose management wheel 11 (Figure 2) and a toothed part 25 of the rod 13 of piston. When the injection is complete, the button 7 for pressing and the item 5 for dose setting return to their "initial positions, ready for the establishment of another dose." If the injection syringe 1 is to be used by diabetics who require injections regular insulin, projections 21, preferably are of a size corresponding to 1 UI (International Unit), so that each click that is heard when set in the dose, corresponds to 1 UI, which provides the user with an indication audible of the dose that is established together with a visual indication on scale 9. It also means that the dose can be adjusted very accurately with a whole number of international units In the mode shown, the coupling ring 12 surrounds the wheel 11 of dose administration In an alternative embodiment, the dose management wheel that surrounds the coupling ring, the administration wheel of The dose is provided with projections on its outer periphery, and the coupling ring is provided with projections on its outer periphery. Therefore, if an established dose is to be corrected, the coupling ring should be placed in such a way that it does not expand but contract, which allows the projections of the dose management wheel and the coupling ring slide one in relation to the other. The design of the injection syringe need not be in the form of a pen as shown, but may be compact in shape having a flexible piston rod surrounding the gear wheel of the dose management wheel. This provides an injection syringe which is a very portable unit that has a size that fits the hand of an adult. In a special embodiment of this type of injection syringe, an additional gear wheel can be placed between the gear wheel of a dose management wheel and the flexible piston rod in order to ensure that a relatively large change in the The angular position of the dose setting element causes a small change in the amount of medicine to be injected. Therefore, the adjustment of the dose can be performed with remarkable precision. Preferably, the injection syringe 1 in its entirety is made of a plastic material in order to render it disposable after use, which is considered environmentally correct, but it can also be manufactured from other materials such as metals or any combination of materials . The injection syringe can be a disposable type, or it can be of the reusable type in which the ampoule can be replaced when it is empty. However, the reusable type requires a special arrangement to retract the piston rod from its position further forward. . Although the dose setting mechanism has been described in relation to an injection syringe, the dose adjustment mechanism can be applied to other drug delivery devices in which individual doses of the medication to be administered can be established. It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects or products to which it refers.

Claims (9)

CLAIMS Having described the invention as above, the content of the following claims is claimed as property:

1. A dose adjustment mechanism for a medication delivery device, the device has a housing, a piston rod and a push button, connectable to the piston rod for administration of a dose set from a container, the mechanism of The dose adjustment comprises a rotatable dose adjustment element interconnected with the button for pressing, characterized in that the dose adjustment mechanism further comprises a dose management wheel connected to the piston rod, and a coupling ring connected to the element of dose adjustment and the button to press, one of the dose management wheel and the coupling ring, which at least partially surrounds the other, the dose management wheel and the coupling ring are placed so that the rotation of the dose adjustment element allows the coupling ring to be rotated in any direction in relation to the a dose management wheel, while the activation of the button to press, and therefore the rotation of the coupling ring, causes the dose management wheel to rotate, and further characterized because: the dose adjustment element is switched on to the coupling ring; - the coupling ring of the button for pressing is connected so that the rotation of the dose adjusting element and therefore the coupling ring causes the button to press to move up and down; - wherein the downward movement of the button for pressing causes the coupling ring to rotate, the coupling ring and the dose management wheel are positioned so that this rotation causes the coupling ring to engage the steering wheel of dose and in this way spin the wheel; and wherein the dose management wheel is connected to the piston rod so that rotation of the dose management wheel causes the piston rod to move forward.

2. The dose adjustment mechanism, according to claim 1, characterized in that the dose management wheel is provided with projections on its outer periphery, so that the coupling ring consists of a ring segment that partially surrounds the wheel of dose administration and is rigidly connected with a hub at one end, and flexibly connected to the hub at the other end, the ring segment is provided with projections on at least part of its inner side, and wherein the connection between the dose adjustment element and the coupling ring is provided at the end of the ring segment which flexibly connects with the hub.

3. The dose adjusting mechanism, according to claim 2, characterized in that the coupling ring is connected to the button for pressing by means of a gear wheel that is provided in the center of the coupling ring and a toothed part of the button to press.

4. An injection syringe, comprising a housing accommodating an ampoule containing sufficient medicine for several metered injections, a button for pressing for injection, a piston rod, for cooperation with a piston in the ampule when the injection is made, and a dose adjustment mechanism comprising a rotatable dose adjustment element interconnected with the push button, characterized in that the dose adjustment mechanism further comprises a dose-1-dose delivery wheel connected to the piston rod and a ring of coupling connected with the dose adjustment element and the button for pressing, one of the dose management wheel and the coupling ring at least partially surrounds the other, the dose management wheel and the coupling ring are positioned so that the rotation of the dose adjusting element allows the coupling ring to rotate in any direction relative to the dose management wheel, while the activation of the button to press, and therefore the rotation of the coupling ring causes the dose management wheel to rotate, and further characterized in that: the dose adjustment element is connected to the coupling ring; - the coupling ring and the button for pressing are connected so that the rotation of the dose adjusting element and therefore of the coupling ring causes the button to press to move up and down; - wherein the downward movement of the button for pressing causes the coupling ring to rotate, the coupling ring and the dose management wheel are positioned so that this rotation causes the coupling ring to engage the steering wheel of dose and in this way spin the wheel; and wherein the dose management wheel is connected to the piston rod so that rotation of the dose management wheel causes the piston rod to move forward.

5. The injection syringe, according to claim 4, characterized in that the dose management wheel is provided with projections on its outer perry, wherein the coupling ring consists of a ring segment that partially surrounds the delivery wheel of dose and which is rigidly connected to a hub at one end, and flexibly connected to the hub at the other end, the ring segment is provided with projections on at least part of its inner side, and wherein the connection between the element of dose setting and the coupling ring is provided at the end of the ring segment which is flexibly connected to the hub.

6. The injection syringe according to claim 5, characterized in that the coupling ring is connected to the button for pressing by means of a gear wheel which is provided in the center of the coupling ring and a toothed part of the button for pressing.

7. The injection syringe according to any of claims 4 to 6, characterized in that the dose management wheel and the housing have cooperating means to prevent the dose management wheel from rotating in a direction corresponding to the removal of the dose rod. Blister piston.

8. The injection syringe according to any of claims 4 to 8 characterized in that the dose management wheel is connected to the piston rod by means of a gear wheel that is provided in the center of the dose management wheel.

9. The injection syringe according to any of claims 4 to 8, characterized in that the dose adjustment element is provided with a scale and wherein the housing is provided with an indicator pointing to the scale, the indicator indicates the established dose when the dose adjustment element is rotated.